1. Technical Field
The present invention relates generally to a dielectric resonator antenna embedded in a multilayer substrate for enhancing bandwidth.
2. Description of the Related Art
Mainly, products for a conventional transmission/reception system have been constructed by assembling individual parts into each system. However, research into System On Package (SOP) products in which a millimeter-wave band transmission/reception system is implemented as a single package has recently been conducted, and some products have been commercialized.
Technology related to SOP products has been developed along with technology related to a multilayer substrate manufacturing process which stacks dielectric substrates such as Low Temperature Co-fired Ceramic (LTCC) and Liquid Crystal Polymer (LCP) substrates.
Such a multilayer substrate package is manufactured using a single manufacturing process by embedding passive elements in a package as well as by integrating Integrated Circuits (ICs) which are active elements. Accordingly, there are effects in which an inductance component can be reduced thanks to reduced usage of conducting wires and in which loss attributable to coupling between elements can also be reduced, and there is an advantage in that the costs of manufacturing products can be retrenched.
However, in the case of an LTCC manufacturing process, a substrate may be contracted by about 15% in the x and y directions, which are planar directions of the substrate, during plastic working. Accordingly, fabrication errors occur, and thus a problem may arise from the standpoint of the reliability of products.
In a multilayer structure environment such as in LTCC and LCP manufacturing processes, a patch antenna having planar characteristics is mainly used, but has a disadvantage of a narrow bandwidth of about 5%.
In order to overcome such a disadvantage, methods of widening the bandwidth in such a way as to cause multiple resonances by adding a parasitic patch to the same plane as that of a patch antenna functioning as a main radiator or in such a way as to induce multiple resonances by stacking two or more patch antennas, have been used.
It is known that bandwidth of about 10% can be obtained using such a conventional multi-resonance technique.
However, when the conventional multi-resonance technique is used, differences may occur between the radiation patterns of an antenna at individual resonant frequencies, and variations in the characteristics of the antennas depending on fabrication errors in the multi-resonance antenna may be greater than in a single-resonance antenna.
Therefore, in order to increase the efficiency of such an antenna and ensure a wider bandwidth, a conventional Dielectric Resonator Antenna (DRA) is occasionally used.
It is known that such a conventional dielectric resonator antenna has more excellent bandwidth and efficiency characteristics than the above-described conventional patch antenna using a multi-resonance technique.
The conventional dielectric resonator antenna is frequently used to overcome the disadvantages of the conventional patch antenna, but it requires a separate dielectric resonator disposed outside a substrate, and thus there is the inconvenience of manufacturing processes compared to a stacked patch antenna implemented using a single manufacturing process.
Further, a conventional dielectric resonator antenna can ensure a wider bandwidth because multiple resonances occur as the size of a dielectric resonator (for example, the length of the dielectric resonator in a direction which does not influence resonant frequency) increases. In contrast, such a dielectric resonator antenna is disadvantageous in that the to radiation patterns thereof are deformed within the bandwidth.